The invention relates to an inlet gate or ingate device for casting molten metal, and more particularly to an ingate device having an inlet channel for receiving molten metal, an outlet channel for conveying the molten metal to a mold, and a rotation chamber connecting the inlet and outlet channels to separate nonmetallic materials from the molten metal, as well as to a process for casting molten metal using an ingate device.
The increasing demands to improve the purity of castings and to decrease the manufacturing costs by reducing the cleaning and secondary treatment have prompted attempts to improve casting methods. Pouring techniques have been improved by providing pouring basins with dividing walls and/or constrictions to absorb the slag and nonmetallic inclusions from the molten metal. Furthermore so-called whirlgate dirt traps and whirl-runners or rotary chambers are known.
German Patent specification No. 2,159,964 describes such a whirl-runner, which is used primarily for high-alloyed steel casting for reactor parts, pumps, turbine casings, etc. This well-known whirl-runner employs a rotation chamber consisting of at least three elements shifted on top of each other, each composed of parts independently exchangeable with the other elements. This whirl-runner can be used only once.
Furthermore German Offenlegungsschrift No. 2,950,393 describes a separator which is made of gasifiable plastic, embedded in the casting mold. This separator can also only be used once. Furthermore it has the disadvantage--because its wall essentially consists of rammed molding sand--that it is very susceptible to erosion and thus can become the source of nonmetallic inclusions.